Pendulum switch assembly for clocks or the like with electromagnetic impulse means

ABSTRACT

A pair of terminals are arranged one on either side of the vertical rest position of a main pendulum. An inverted secondary pendulum is pivotally mounted on the main pendulum such that oscillations of the main pendulum induces synchronous oscillation of the secondary pendulum between and into and out of contact with the terminals whereby the secondary pendulum is usable as a switching member.

United States Patent [191 Curran 1 PENDULUM SWITCH ASSEMBLY FOR CLOCKS OR THE LIKE WITH ELECTROMAGNETIC IMPULSE MEANS Samuel Crowe Curran, University of Strathclyde Royal College, 204 .George St., Glascow, Scotland Filed: Oct. 11, 1972 Appl. No.: 296,568

Inventor:

Foreign Application Priority Data Oct. 14, 1971 Great Britain 47,756/71 US. Cl. 58/30, ZOO/61.51, 335/90 Int. CL... G04c 3/02, HOlh 35/02, HOlh 51/34 Field of Search ZOO/61.48, 61.49,

ZOO/61.50, 61.51; 335/69, 70, 90, 191; 58/30 References Cited UNITED STATES PATENTS 5/1950 McNerney ZOO/61.51

Primary Examiner-James R. Scott Artorney- Mason, Fenwick & Lawrence 57 ABSTRACT A pair of terminals are arranged one on either side of the vertical rest position of a main pendulum. An inverted secondary pendulum is pivotally mounted on the main pendulum such that oscillations of the main pendulum induces synchronous oscillation of the secondary pendulum between and into and out of contact with the terminals whereby the secondary pendulum is usable as a switching member.

12 Claims, 7 Drawing Figures PATENTED JAN 8 4 SHEET 1 [1F 3 PATENTEDJAN 8W4 I 3,783,601

SHEET 2 [IF 3 PENDULUM SWITCH ASSEMBLY FOR CLOCKS OR THE LIKE WITH ELECTROMAGNETIC IMPULSE MEANS This invention concerns improvements in or relating to switches. I

A pendulum may be maintained efficiently in oscillation by the application of a sustaining force properly timed with reference to the motion of the pendulum itself. The force should be applied in the direction of motion of the pendulum and the amount of the force should be adjusted to compensate for the energy losses sustained.

According to the present invention there is provided a pendulum switch including a support, a main pendulum, first'pivot means mounting the main pendulum about its upper end on the support for oscillation in a first vertical plane, a secondary pendulum, second pivot means mounting the secondary pendulum about its lower end on the main pendulum for oscillation in said first vertical plane or a plane parallel thereto, a contact point on the secondary pendulum, and a pair of terminals mounted on the support and disposed one on either side of the vertical position of the main pendulum, said terminals projecting into the path of travel of said contact point, whereby oscillation of the main pendulum causes the secondary pendulum to pivot under the action of gravity between and into and out of contact with said terminals in'synchronism with the oscillation' of the main'pendulum.

The switch may be used in a variety of applications, preferably for operating a' time-keeping or recording device but also, for example,in an accelerometer or Tapley meter for measuring or controlling acceleration or a braking force.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a schematic front elevational view of a'pendulum switch;

FIG. 2 is a schematic side view of FIG. 1;

FIG. 3 is a schematic front elevational view showing part of the pendulum switch enclosed in a sealed vessel;

FIG. 4 is a schematic side view of FIG. 3; and

FIG. 5 is a schematic diagram illustrating the circuitry and essential features of electromagnetic impulse means and an an escapemerlt mechanism of the pendulum switch shown in FIG. 1;

FIG. 6 is a schematic front elevational view illustrating a modification of part of the pendulum switch; and

FIG. 7 is a schematic sectional side view of the modified pendulum switch shownin-FIG. 6.

support 3 are symmetrically arranged about the vertical rest position of the main pendulum 1 and in the path of travel of the contact point 4a so that the contact point 4a can move between and into and out of contact with the terminals 6. The terminals 6 are preferably set at right angles to the plane of motion of the main pendulum l. 1

In operation, when the main pendulum l is set in motion its oscillation causes the secondary pendulum to pivot under the action of gravity between and into and out of contact with the terminals 6 in synchronism with the oscillations of the main pendulum 1. As the second pivot 5 of the secondary pendulum 4 passes in either direction of swing below one of the terminals 6 the secondary pendulum is caused to fall back automatically on to the other terminal ,where it temporarily rests.

' Thusthe contact point on the secondary pendulum With'reference to FIGS. 1 and 2 a main pendulum 1 v has a first pivot 2 ator near its upper end and is pivotally supported by a fixed support 3 so that. the mainpendulum is oscillatable about the first pivot 2 in a first vertical plane. A secondary pendulum 4 has a second pivot 5 at or near its lower end and a contact point 4a rests against one or other terminal during most of the time of oscillation of the main pendulum oscillation of the secondary pendulum between the terminals being induced as the main pendulum oscillates.

The movements of both pendulums are synchronous and the second pendulum can be used directly as a switching member the movements whereof are timed,or as an actuating mechanism for a subsidiary switching system.

By making the secondary pendulum 4 and the terminals 6 electrically conducting, and by providing an electrical insulator 7 between the secondary pendulum and the main pendulum and between the terminals 6 and the fixed support 3, the secondary pendulum can be utilised asa switching member for two electric circuits connected between each of said terminals and said secondary pendulum.

To improve the reliability of the switching process the essential operating parts of the switch may be enclosed in a gas-filled or evacuated sealed vessel 8 which is fixedly secured to either the main pendulum itself or a supporting arm 9 on the main pendulum (FIG. 4). In this case the terminals 6 on the fixed support 3 act simply as mechanical stops, two electrially conducting contacts 6a being provided on the inside of the sealed vessel 8 so that the make-and-break action of the secondary pendulum switch takes place within said vessel.

' Alternatively, the automatic oscillationof the secondary pendulum may be used to actuate other devices such as fluidic switches or conducting reed switches to create a programmed flow or conducting circuit in a sequence determined by the movement of the main pendulum. For example, FIGS. 6 and 7 illustrate apendulum switch having a reed switch 20 fixedly mounted former 11 is mounted on the main pendulum l and a permanent magnet 12 of cylindrical form and having a central pole 13 is located on the fixed support 3 so that the coil 10 can move to-and-fro in the field of the magnet 12 as the main pendulum oscillates. Thus, by incorporating the coil 10 into each of the two electric circuits connected between the terminals and the secondary pendulum and providing each of these circuits with a source of electricity of opposite polarity l4 and 14a respectively, a magnetic field is produced by the coil which reacts with the magnetic field of the permanent magnet 12 to provide a sustaining force which maintains the oscillation of the main pendulum. It is, of course, understood that the relative positions of the magnet and the coil can be reversed. The amount of current which passes in the associated electrical circuit and which provides the sustaining force may be varied within fairly wide limits and such a system has proved stable and reliable in operation. The current may be produced by an electrical cell or cells 14 and 14a of opposite polarity or by means of any other suitable direct current generator. In the FIG. 5 the sustaining force is secured in both to and fro motion but this arrangement can be simplified so that the sustaining force is applied in only one of the two directions of motion.

By adjusting the length of the secondary pendulum or its positioning between the terminals 6 (FIG. 1) the timing of the sustaining force can be sensitively adjusted.

The above application can be used to power various devices. For example, a gravity sensitive arm 15 or other device may be secured, for example pivotted, to the pendulum and used to rotate a wheel 16. Thus a pawl may be used to drive a toothed wheel which can perform the same function as an escapement mechanism associated with driving the hands of a clock. It is possible to couple the wheel, which has effectively a fixed number of rotations per unit of time, to other wheels or hands by means of gravity sensitive levers similar to the one which couples it to the pendulum so that a variety of time-keeping or recording devices may be afforded, with a high degree of accuracy and efficiency.

One presently preferred form of the invention is embodied in a kit comprising the various elements of a clock operated by the switch described above, these elements being packaged in disassembled form and being capable of repeated assembly and disassembly for educational purposes or occupational therapy.

The invention may also be utilised as a high precision, extremely simple clock having all operating parts displayed to an observer and offering long stable operation of high efficiency when powered by an inexpensive form of electrical cell. The sustaining force can be applied in one direction only or during both directions of motion.

I claim:

1. A pendulum switch including a support, a main pendulum, first pivot means mounting said main pendulum about its upper end on said support for oscillation in a first vertical plane, a secondary pendulum, second pivot means mounting said secondary pendulum about its lower end on said main pendulum for oscillation in said first'vertical plane or a plane parallel thereto, a contact point on said secondary pendulum, and a pair of terminals mounted on said support and disposed one on either side of the vertical position of said main pendulum, said terminals projecting into the path of travel of said contact point, whereby oscillation of said main pendulum causes said secondary pendulum to pivot under the action of gravity between and into and out of contact with said terminals in synchronism with the oscillation of said main pendulum.

2. A pendulum switch as claimed in claim 1, including electromagnetic impulse means for applying a sustaining force to said main pendulum to maintain oscillation thereof.

3'. A pendulum switch as claimed in claim 2, wherein said secondary pendulum and terminals are formed of electrically conductive material, and an electrical insulator is interposed between said secondary pendulum and said main pendulum and between said contacts and said support, whereby said secondary pendulum is usable as a switching member for two electric circuits connected between each of said terminals and said secondary pendulum for the actuation of said electromagnetic impulse'means.

4. A pendulum switch as claimed in claim 3, wherein said electromagnetic impulse means includes a coil member forming part of each of said two electric circuits, and a permanent magnetic member, one of said members being mounted on said main pendulum and the other on said support in the path of travel of said one member and each of said two electric circuitshaving a source of electricity of opposite polarity to each other, connected in series with said coil member, whereby said sustaining force is applied to said main pendulum in both directions of motion thereof.

5. A pendulum switch as claimed in claim 4, including an escapement mechanism operable by the oscillations of said main pendulum by means of a pawl and toothed wheel. I

6. A pendulum switch as claimed in claim 5, including first adjustment means on said support for adjusting the positions of said terminals relative to the vertical position of said main pendulum to alter the time sequence of the oscillations of said secondary pendulum.

relative to those of said pendulum.

7. A pendulum switch as claimed in claim 6, including second adjustment means on said secondary pendulum for adjusting the length thereof to alter the time sequence of its oscillations relative to. those of said main pendulum.

8. A pendulum switch as claimed in claim 2, including a reed switch fixedly mounted on each of said terminals, and a permanent magnet fixedly mounted on said secondary pendulum at said contact point to actuate each of said reed switches as said magnet alternatively moves into and out of contact with each of said reed switches whereby said secondary pendulum is usable as a switching member for two electric circuits connected between each of said terminals and said secondary pendulum for the actuation of said electromagnetic impulse means.

9. A pendulum switch as claimed in claim 8, wherein said electromagnetic impulse means includes a coil member forming part of each of said two electric circuits, and a permanent magnetic member, one of said members being mounted on said main pendulum and the other on said support in the path of travel of said one member, each of said two electric circuits having a source of electricity of opposite polarity to each other connected in series with said coil member, whereby said sustaining force is applied to said main pendulum in both directions of motion thereof.

10. A pendulum switch as claimed in claim 9, including an escapement mechanism operable by the oscillations of said main pendulum by means of a pawl and toothed wheel.

11. A pendulum switch as claimed in claim 10, including first adjustment means on said support for adjusting said positions of the terminals relative to the vertical position of said main pendulum to alter thetime sequence of the oscillations of said secondary pendulum relative to those of said main pendulum.

main pendulum. 

1. A pendulum switch including a support, a main pendulum, first pivot means mounting said main pendulum about its upper end on said support for oscillation in a first vertical plane, a secondary pendulum, second pivot means mounting said secondary pendulum about its lower end on said main pendulum for oscillation in said first vertical plane or a plane parallel thereto, a contact point on said secondary pendulum, and a pair of terminals mounted on said support and disposed one on either side of the vertical position of said main pendulum, said terminals projecting into the path of travel of said contact point, whereby oscillation of said main pendulum causes said secondary pendulum to pivot under the action of gravity between and into and out of contact with said terminals in synchronism with the oscillation of said main pendulum.
 2. A pendulum switch as claimed in claim 1, including electromagnetic impulse means for applying a sustaining force to said main pendulum to maintain oscillation thereof.
 3. A pendulum switch as claimed in claim 2, wherein said secondary pendulum and terminals are formed of electrically conductive material, and an electrical insulator is interposed between said secondary pendulum and said main pendulum and between said contacts and said support, whereby said secondary pendulum is usable as a switching member for two electric circuits connected between each of said terminals and said secondary pendulum for the actuation of said electromagnetic impulse means.
 4. A pendulum switch as claimed in claim 3, wherein said electromagnetic impulse means includeS a coil member forming part of each of said two electric circuits, and a permanent magnetic member, one of said members being mounted on said main pendulum and the other on said support in the path of travel of said one member and each of said two electric circuits having a source of electricity of opposite polarity to each other, connected in series with said coil member, whereby said sustaining force is applied to said main pendulum in both directions of motion thereof.
 5. A pendulum switch as claimed in claim 4, including an escapement mechanism operable by the oscillations of said main pendulum by means of a pawl and toothed wheel.
 6. A pendulum switch as claimed in claim 5, including first adjustment means on said support for adjusting the positions of said terminals relative to the vertical position of said main pendulum to alter the time sequence of the oscillations of said secondary pendulum relative to those of said pendulum.
 7. A pendulum switch as claimed in claim 6, including second adjustment means on said secondary pendulum for adjusting the length thereof to alter the time sequence of its oscillations relative to those of said main pendulum.
 8. A pendulum switch as claimed in claim 2, including a reed switch fixedly mounted on each of said terminals, and a permanent magnet fixedly mounted on said secondary pendulum at said contact point to actuate each of said reed switches as said magnet alternatively moves into and out of contact with each of said reed switches whereby said secondary pendulum is usable as a switching member for two electric circuits connected between each of said terminals and said secondary pendulum for the actuation of said electromagnetic impulse means.
 9. A pendulum switch as claimed in claim 8, wherein said electromagnetic impulse means includes a coil member forming part of each of said two electric circuits, and a permanent magnetic member, one of said members being mounted on said main pendulum and the other on said support in the path of travel of said one member, each of said two electric circuits having a source of electricity of opposite polarity to each other connected in series with said coil member, whereby said sustaining force is applied to said main pendulum in both directions of motion thereof.
 10. A pendulum switch as claimed in claim 9, including an escapement mechanism operable by the oscillations of said main pendulum by means of a pawl and toothed wheel.
 11. A pendulum switch as claimed in claim 10, including first adjustment means on said support for adjusting said positions of the terminals relative to the vertical position of said main pendulum to alter the time sequence of the oscillations of said secondary pendulum relative to those of said main pendulum.
 12. A pendulum switch as claimed in claim 11, including second adjustment means on said secondary pendulum for adjusting the length thereof to alter the time sequence of its oscillations relative to those of said main pendulum. 